1. Field of the Invention
The invention relates to a switch, more particularly to a switch that has a ball member.
2. Description of the Related Art
Referring to FIGS. 1 to 3, a conventional switch 10, as disclosed by the applicant in U.S. Pat. No. 6,800,841, includes an insulating housing body 11, an emitter 12, a receiver 13, a modular insert body 14, a ball member 15, and a modular cover 16.
The housing body 11 has a top opening, and includes a bottom wall 111, a surrounding wall 113 extending upwardly from a peripheral end of the bottom wall 111 and cooperating with the same to define a first chamber 112, spaced-apart first and second partition walls 114, 115 extending upwardly from the bottom wall 111 into the first chamber 112, a first slot 116 formed in the first partition wall 114, and a second slot 117 formed in the second partition wall 115.
The emitter 12 includes an emitter body 121 disposed between the first partition wall 114 and the surrounding wall 113, an emitter head 122 projecting from the emitter body 121 into the first slot 116, and two contact terminals 123-projecting downwardly from the emitter body 121 and extending through the bottom wall 111 of the housing body 11.
The receiver 13 includes a receiver body 131 disposed between the second partition wall 115 and the surrounding wall 113, a receiver head 132 projecting from the receiver body 131 into the second slot 117, and two contact terminals 133 projecting downwardly from the receiver body 131 and extending through the bottom wall 111 of the housing body 11. The receiver head 132 and the emitter head 122 cooperatively form a light path (I).
The modular insert body 14 is disposed in the first chamber 112 between the first and second partition walls 114, 115, and includes an end wall 141 abutting against the first partition wall 114, a cylindrical peripheral wall 143 extending outwardly toward the second partition wall 115 from a peripheral end of the end wall 141 and cooperating with the same to define a second chamber 142, and an aperture 144 formed in the end wall 141 and aligned with the emitter and receiver heads 122, 132 along the light path (I). The second chamber 142 has a tapered portion 145 that converges from the peripheral wall 143 to the aperture 144.
The ball member 15 is rollable within the second chamber 142 to block or unblock the light path (I).
The modular cover 16 covers the top opening of the housing 11, and includes a top wall 161, and two press pieces 162 projecting downwardly from the top wall 161 so as to press respectively against the emitter and receiver bodies 121, 131.
In use, the contact terminals 123, 133 of the emitter 12 and the receiver 13 are fixed on a circuit board 17. With reference to FIG. 2, when the circuit board 17 is parallel to a reference horizontal surface (II), the ball member 15 unblocks the light path (I), so that light emitting from the emitter head 122 can-pass through the aperture 144 and be received by the receiver head 132. The switch 10 is in an “ON” state at this time.
With reference to FIG. 3, when the switch 10 is turned such that the circuit board 17 is perpendicular to the reference horizontal surface (II) and the receiver head 132 is above the emitter head 122, the ball member 15 rolls toward the aperture 144 so as to block the light path (I), thereby placing the switch 10 in an “OFF” state.
Although the aforementioned switch 10 can achieve its intended purpose, when the ball member 15 rolls to the second partition wall 115 or toward an area adjacent to the second slot 117 during movement of a device to which the switch 10 is applied, the ball member 15 can undesirably interfere with the light so that the light is not received by the receiver head 132. This increases the incidence of erroneous operation of the switch 10.